In peristaltic pumps a flexible tube is compressed between rollers that are carried by a rotor and travel along a circular path and a race with a surface adjacent to and concentric with the path of the rollers. As the occluded portion of the tube is advanced, the fluid in front of it is forced to travel through the tube. In some pumps the tube is maintained in proper position on the rollers through the use of guides that are on the rotor and move with respect to the tube.